EREG overexpression enhanced cell migration, invasion, structure of actin cytoskeleton in vitro and lung metastasis in vivo. A. F-actin cytoskeleton structure of EC9706 and Kyse30 was visualized by immunofluorescence analysis. B. Representative images of spheroid colonies were shown. C. Self-renewal ability was investigated by mammosphere assays in serum free medium. D. Flow cytometry analysis of CD44+ population. E. Number of lung metastasis foci formed by EC9706-EREG, Vector and EC9706 parental cells in the nude mice. F. Kaplan-Meier survival curve of mice injected with EC9706-EREG, Vector and EC9706 parental cells. G. The effects of EREG on EGFR activation, phosphorylated EGFR, FAK or Src in EC9706 cells with or without overexpression of EREG were analyzed by Western Blot.